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Identification of Staphylococcus aureus exotoxins by combined sodium dodecyl sulfate gel electrophoresis and matrix‐assisted laser desorption/ ionization‐time of flight mass spectrometry
Author(s) -
Bernardo Katussevani,
Fleer Silke,
Pakulat Norbert,
Krut Oleg,
Hünger Frank,
Krönke Martin
Publication year - 2002
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/1615-9861(200206)2:6<740::aid-prot740>3.0.co;2-m
Subject(s) - gel electrophoresis , staphylococcus aureus , microbiology and biotechnology , sodium dodecyl sulfate , chemistry , western blot , virulence , matrix assisted laser desorption/ionization , tryptic soy broth , mass spectrometry , polyacrylamide gel electrophoresis , chromatography , biology , biochemistry , bacteria , enzyme , desorption , adsorption , gene , genetics , organic chemistry
Staphylococcus aureus is an important human pathogen whose pathogenesis involves the synthesis of cell wall associated virulence factors and secreted toxins with damaging effects on the host cells. Most of these pathogenic factors are synthesized in a growth‐phase dependent manner as a response to environmental stress like heat, lack of nutrients or other deleterious conditions. Conventional identification of these pathogenic factors is based on Western blot analysis or enzyme‐linked immunosorbent assay (ELISA) and is limited by the commercial availability of antibodies against these toxins. We report here the use of matrix‐assisted laser desorption/ionization‐time of flight (MALDI‐TOF) mass spectrometry for monitoring the pathogenic factors of S. aureus . For the identification of pathogenic factors, a methicillin sensitive strain of S. aureus, ATCC‐29213, was grown at 37°C or 42°C in brain‐heart infusion broth and harvested during the early stationary phase of growth. Secreted proteins were separated by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis, enzymatically digested with trypsin and analyzed by MALDI‐TOF mass spectrometry. When grown at 42°C, alpha‐ and beta‐hemolysins were found to accumulate in S. aureus supernatants while the concentration of protein A was slightly decreased. The identity of some of these toxins was confirmed by Western‐blot analysis. MALDI‐TOF mass spectrometry combined with sodium dodecyl sulfate gel electrophoresis represents a rapid and simple approach to characterize the virulence of S. aureus strains which seems to be particularly valuable for the identification of S. aureus exotoxins for which ELISA is not established.